The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Eric Bertoft - One of the best experts on this subject based on the ideXlab platform.
-
Observations on the impact of amylopectin and amylose structure on the swelling of starch granules
Food Hydrocolloids, 2020Co-Authors: Varatharajan Vamadevan, Eric BertoftAbstract:Abstract Four different types of amylopectin structure have been reported in our earlier work based on the internal unit chain profile obtained from limit dextrins of amylopectin and data strongly suggested that chain length and organization of internal unit chains of amylopectin influence the gelatinization and retrogradation properties of the starch. Another important functional attribute is granule swelling that mainly contributes to the viscosifying property of starches. In this study, unmodified defatted amylose-containing starch granules possessing amylopectin of four types were subjected to swelling in warm water. The swelling pattern of the granules was related to the structural type of the amylopectin component. Granules having amylopectin of Type 1 structure started to swell at lower temperature (about 55 °C) and possessed more restricted swelling than most of the other starches. Type 1 starches lost their integrity at temperatures above 85 °C, whereas starch granules with Type 2 and 3 amylopectin were still intact at 95 °C. Starches with Type 4 amylopectin were heterogeneous with respect to their swelling: Lesser yam starch possessed comparatively restricted swelling between 75 and 95 °C, whereas canna and potato starch swelled extensively and disintegrated already before 95 °C. Some waxy samples were also included in the investigation and these were generally more sensitive to swelling than their non-waxy counterparts, showing that amylose restricts the swelling and stabilizes the granular structure, albeit there was no correlation between the apparent amylose content and the swelling of tested samples. Instead, the result suggested a correlation between the structure of amylopectin and the deposition of amylose in the starch granules.
-
Impact of different structural types of amylopectin on retrogradation
Food Hydrocolloids, 2018Co-Authors: Varatharajan Vamadevan, Eric BertoftAbstract:Abstract Retrogradation is the re-association and recrystallization process of glucan chains in gelatinized starch. The objective of the study was to investigate the effect of amylopectin structure on re-association of glucan chains during retrogradation. Amylopectin retrogradation of 17 starches from four different structural types was examined by differential scanning calorimetry (DSC). Gelatinized starches were stored for 10 days at 4 °C and then scanned from 10–120 °C at 10 °C/min. The structural type of amylopectin influenced the transition temperatures (Tm and Tc), melting temperature range (Tc–To) and enthalpy change of transition (ΔH). Correlation analysis between different chain length categories and the melting parameters of recrystallized amylopectin revealed a strong correlation of the external chain length (ECL) with Tm (r = 0.90, p
-
Fine Structure of Amylopectin
Starch, 2015Co-Authors: Eric BertoftAbstract:Starch granules consist of two major polyglucans, namely, branched amylopectin and essentially linear amylose. In all nonmutant starches, amylopectin is the major component and is responsible for the internal structure of starch granules, which is the native, semicrystalline form of starch. The granules, irrespective of the plant source, consist of granular rings of alternating amorphous and semicrystalline polymers. On a smaller scale, blocklets as well as crystalline and amorphous lamellae have been identified. Amylopectin is generally accepted as the contributor to the lamellar structure, but the nature of blocklets is only beginning to be resolved. Amylopectin consists of numerous chains of glucosyl units that are divided into short and long chains. These chains are organized as clusters that have been isolated by using endo-acting enzymes, and the fine structure of the clusters have been investigated. The clusters consist of still smaller, tightly branched units known as building blocks. The organization of the clusters and building blocks in the macromolecular structure of amylopectin is to date uncertain, and two schools exist at present suggesting that amylopectin either has a treelike branched cluster structure or a building block backbone structure. The structural features of amylopectin and the two models presently in debate are discussed in this chapter.
-
Unit and Internal Chain Profile of Millet Amylopectin
Cereal Chemistry, 2014Co-Authors: George Amponsah Annor, Eric Bertoft, Massimo F. Marcone, Koushik SeetharamanAbstract:ABSTRACT The unit chain compositions of debranched foxtail, proso, pearl, and finger millet Amylopectins and their ϕ,β-limit dextrins were analyzed by high-performance anion-exchange chromatography. The ϕ,β-limit dextrins reflected amylopectin internal chain profiles. The Amylopectins had average chain lengths ranging from 17.94 to 18.12. The ranges of external chain length, internal chain length, and total internal chain length of the millet Amylopectins were 11.85–12.33, 4.75–5.09, and 11.64–12.28, respectively. The relative molar concentration of B-chains in the Amylopectins was close to 50% in all samples. Significant differences were, however, observed in the proportions of very short “fingerprint” B-chains (Bfp, degree of polymerization 3–7) and the major group of short B-chains (BSmajor): foxtail and proso millets possessed high amounts of Bfp-chains, whereas finger and pearl millets had higher amounts of BSmajor-chains, suggesting possible differences in the fine structure of the clusters and buil...
-
composition of clusters and building blocks in Amylopectins from maize mutants deficient in starch synthase iii
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Eric Bertoft, Koushik SeetharamanAbstract:Branches in amylopectin are distributed along the backbone. Units of the branches are building blocks (smaller) and clusters (larger) based on the distance between branches. In this study, composition of clusters and building blocks of Amylopectins from dull1 maize mutants deficient in starch synthase III (SSIII) with a common genetic background (W64A) were characterized and compared with the wild type. Clusters were produced from Amylopectins by partial hydrolysis using α-amylase of Bacillus amyloliquefaciens and were subsequently treated with phosphorylase a and β-amylase to produce φ,β-limit dextrins. Clusters were further extensively hydrolyzed with the α-amylase to produce building blocks. Structures of clusters and building blocks were analyzed by diverse chromatographic techniques. The results showed that the dull1 mutation resulted in larger clusters with more singly branched building blocks. The average cluster contained ∼5.4 blocks in dull1 mutants and ∼4.2 blocks in the wild type. The results a...
M Van Bruijnsvoort - One of the best experts on this subject based on the ideXlab platform.
-
retention behaviour of Amylopectins in asymmetrical flow field flow fractionation studied by multi angle light scattering detection
Journal of Chromatography A, 2001Co-Authors: M Van Bruijnsvoort, Karlgustav Wahlund, Gunilla S NilssonAbstract:Abstract Asymmetrical flow field-flow fractionation (FFF) with multi-angle light scattering (MALS) detection was applied for the fractionation of Amylopectins from four different sources. Samples originated from genetically modified potatoes and waxy maize. Amylopectins were dissolved in a 1 mol l −1 sodium hydroxide solution or water. With an injected mass of 0.2 μg, well below overloading conditions, a decrease of the apparent hydrodynamic radius with increasing inlet flow-rate was observed. Moreover, a decrease of the radius of gyration with increasing elution volume was recorded by the MALS detector. Steric/hyperlayer effects are a feasible explanation for this behaviour. The observed radius of gyration at the steric inversion point was in the order of 0.3 μm, which is smaller than the theoretically calculated inversion point. Apparently, the amylopectin behave as macromolecules with a larger hydrodynamic radius than expected on basis of their radius of gyration and are subjected to significant lift forces. The results were confirmed by four fractionations with varying flow-rates but constant ratio of cross to outlet-flow. In contrast to the normal mode operation, the retention of the Amylopectins depended strongly on the applied flow-rates and was close to that of a much smaller 10 kDa dextran. Apparent molar masses in the order of between 10 7 and 10 9 g mol −1 were obtained. The results are contrasted with enzymatically degraded and oxidised starch samples that were fractionated in the normal mode.
Veronique Planchot - One of the best experts on this subject based on the ideXlab platform.
-
branching features of Amylopectins and glycogen determined by asymmetrical flow field flow fractionation coupled with multiangle laser light scattering
Biomacromolecules, 2007Co-Authors: Agnes Rollandsabate, Paul Colonna, Maria Guadalupe Mendezmontealvo, Veronique PlanchotAbstract:The aim of this work was to characterize starch polysaccharides using asymmetrical flow field flow fractionation coupled with multiangle laser light scattering. Amylopectins from eight different botanical sources and rabbit liver glycogen were studied. Amylopectins and glycogen were completely solubilized and analyzed, and high mass recoveries were achieved (81.7−100.0%). Amylopectin Mw, RG, and the hydrodynamic coefficient νG (the slope of the log−log plot of RGi vs Mi) were within the ranges 1.05−3.18 × 108 g mol-1, 163−229 nm, 0.37−0.49, respectively. The data were also considered in terms of structural parameters. The results were analyzed by comparison with the theory of hyperbranched polymers (Flory, P. J. Principles of Polymer Chemistry; Cornell University Press: Ithaca, NY, 1953; Burchard, W. Macromolecules, 1977, 10, 919−927). This theory, based upon the ABC model, has been shown to underestimate the branching degrees of Amylopectins. However, quantitative agreement with the data in the litera...
Jaylin Jane - One of the best experts on this subject based on the ideXlab platform.
-
Effect of annealing on the semicrystalline structure of normal and waxy corn starches
Food Hydrocolloids, 2012Co-Authors: Thaís De Souza Rocha, Jaylin Jane, Suélen Gleice Felizardo, Célia Maria Landi FrancoAbstract:Abstract The influence of amylose and amylopectin on structural reorganization occurred during annealing was studied for normal and waxy corn starches. Annealing caused an increase in crystallinity in the waxy corn starch, whereas the number of pores on the granule surface, observed by SEM, increased especially for normal corn starch. Amylose and amylopectin chains of the annealed normal corn starch were degraded to greater extension during enzymatic hydrolysis than those of the native starch. On contrary, the annealing caused a protective effect on waxy corn starch amylopectin toward the enzymatic reaction suggesting that this treatment promoted a better interaction between amylopectin chains of waxy corn starch. The amylose molecules of normal corn starch may have impaired the mobility of amylopectin molecules and restricted the reorganization of the crystalline structure during the annealing. The major increase in pores number on the granule surface of annealed normal corn starch, resulted of the endogenous amylase action during annealing, could facilitate the exogenous enzymes’ role in the degradation of the starch granules’ amorphous area.
-
Effects of amylopectin structure on the organization and properties of starch granules
2006Co-Authors: Jaylin Jane, Napaporn Atichokudomchai, Jin-hee ParkAbstract:Amylopectin of waxy starch has a larger molecular weight than that of the normal starch counterpart. Amylose is located side by side, interspersed and intertwined with amylopectin in the normal starch granule. The structures of amylopectin, Naegeli/Lintner dextrin, and starch granules indicate that the short branch-chains of amylopectin, which are located in the middle of the crystalline region of amylopectin, are responsible for the starch crystallization into the orthorhombic unit cell and display the A-type polymorphism. The A-type polymorphic starch also shows voids in the granule, which increase access of enzyme hydrolysis and chemical penetration into the granule. Recent advances in the understanding of the structure of amylopectin and Naegeli/Lintner dextrin are summarized in the chapter. The mechanisms of starch crystallization and the formation of voids in the A-type polymorphic starch are proposed and discussed.
-
Structures and Properties of Amylopectin and Phytoglycogen in the Endosperm of sugary-1 Mutants of Rice
Journal of Cereal Science, 2003Co-Authors: Kit-sum Wong, Jaylin Jane, Akiko Kubo, Kyuya Harada, Hikaru Satoh, Yasunori NakamuraAbstract:Starch debranching enzyme (DBE)-deficient, sugary-1 mutations of rice caused the biosynthesis of more highly branched α-glucan in the form of phytoglycogen and sugary -amylopectin rather than wild-type amylopectin. Phytoglycogen and sugary -amylopectin are located in the inner and outer regions of the rice endosperm, respectively. Detailed analyses of these glucans from a variety of allelic mutants with different severity of sugary phenotype revealed that sugary -Amylopectins consisted of more short chains of DP
-
molecular weights and gyration radii of Amylopectins determined by high performance size exclusion chromatography equipped with multi angle laser light scattering and refractive index detectors
Carbohydrate Polymers, 2002Co-Authors: Jaylin JaneAbstract:Abstract High-performance size-exclusion chromatography (HPSEC) equipped with multi-angle laser-light scattering (MALLS) and refractive index (RI) detectors was used to determine weight-average molecular weight ( M w ) and z -average radius of gyration ( R z ) of amylopectin of selected starches. Ranges of M w and R z values of amylopectin were 7.0×10 7 –5.7×10 9 g/mol and 191–782 nm, respectively. Amylopectins of waxy starches had substantially larger M w than did those of normal starch counterparts. Based on the dispersed-molecular density ( M w / R z 3 ), waxy Amylopectins displayed, in general, larger dispersed-molecular density than did normal amylopectin counterparts, and Amylopectins of the A-type starches had larger dispersed-molecular density than did those of the B-type starches. These results suggested that Amylopectins of waxy starches had more branch-chains and no extra long chains, which resulted in more densely packed molecules than did those of normal starch counterparts. The amylopectin of B-type starch had longer but fewer branch-chains, which resulted in smaller dispersed density than did that of the A-type starch. M w and R z values of amylose isolated from amylomaize VII starch were also determined to be 2.8×10 5 and 43 nm, respectively.
Gunilla S Nilsson - One of the best experts on this subject based on the ideXlab platform.
-
retention behaviour of Amylopectins in asymmetrical flow field flow fractionation studied by multi angle light scattering detection
Journal of Chromatography A, 2001Co-Authors: M Van Bruijnsvoort, Karlgustav Wahlund, Gunilla S NilssonAbstract:Abstract Asymmetrical flow field-flow fractionation (FFF) with multi-angle light scattering (MALS) detection was applied for the fractionation of Amylopectins from four different sources. Samples originated from genetically modified potatoes and waxy maize. Amylopectins were dissolved in a 1 mol l −1 sodium hydroxide solution or water. With an injected mass of 0.2 μg, well below overloading conditions, a decrease of the apparent hydrodynamic radius with increasing inlet flow-rate was observed. Moreover, a decrease of the radius of gyration with increasing elution volume was recorded by the MALS detector. Steric/hyperlayer effects are a feasible explanation for this behaviour. The observed radius of gyration at the steric inversion point was in the order of 0.3 μm, which is smaller than the theoretically calculated inversion point. Apparently, the amylopectin behave as macromolecules with a larger hydrodynamic radius than expected on basis of their radius of gyration and are subjected to significant lift forces. The results were confirmed by four fractionations with varying flow-rates but constant ratio of cross to outlet-flow. In contrast to the normal mode operation, the retention of the Amylopectins depended strongly on the applied flow-rates and was close to that of a much smaller 10 kDa dextran. Apparent molar masses in the order of between 10 7 and 10 9 g mol −1 were obtained. The results are contrasted with enzymatically degraded and oxidised starch samples that were fractionated in the normal mode.